The 'Canadian' Criteria have been with us since 2003, they have been subject to some validation as an effective means of establishing severely impaired 'ME/CFS' sufferers by Leonard Jason et al (2005) and, crucially, have been subject to the most studious of neglect and ignoring, in most subsequent research papers on 'CFS'.

Recently, Lombardi et al's use of the Canadian criteria to select a research patient cohort, and the failure of, specifically, Erlwein et al to reproduce this cohort (but also, I argue , the Kerr team's apparent failure to do same) has highlighted both the failure of scientists to establish a severely impaired research cohort, and the inappropriate extrapolation of results from research cohorts, for which organic dysfunction has been weeded out, to severely impaired patients with signs and symptoms of organic illness (no matter how difficult to 'explain' fully). I think therefore the issue has become extremely timely.

There is a dissonance between what many in the community understand about patient cohorts, and the apparent lack of this by some of the 'scientists'. This is not meant to be inflammatory, but I do think we need to stop excusing scientists for not establishing more 'Canadian' cohorts in ME/CFS research, or at least acknowledging, in the sections of their papers detailing 'limitations of study', the discrepancies between those cohorts like the 'empirical' CDC and Wessley/White Oxford/minimal Fukuda criteria cohorts, and people who should be included in a Canadian defined research cohort, perhaps (I'd say definitely) with the additional abnormal physiological responses detailed in the Lombardi paper.

I have been involved since about 2004 in highlighting the failure of the 'PACE' trial in particular to establish a cohort of patients based on the Canadian guidelines, as well as other scientist's failures to acknowledge the problems of conflicting patient cohorts in their published papers (for example under a section detailing 'limitations of the study') since 2003. I will put up various links and copies of correspondence etc detailing this.

Failure to establish a research cohort of 'Canadian' patients in the UK means there will never be an adequate replication study in the UK. In addition, it has allowed certain unsubtantiated but common claims to be made (e.g. the recent BMJ editorial by Sandthouse et al) that people as ill as, for example, Lynne Gilderdale, are somehow 'rare' and that 'CFS' is treatable by CBT/GET.

I would like this thread to include links to any deliberations on the Canadian Criteria as a research tool, including those arguing against it. In light of some doubt being cast upon the research cohort in the Lombardi et al paper, I am hoping to get that issue clarified as well.

Any evidence people have around the use or non use of Canadian criteria in research settings would be greatly appreciated, as well as deliberations and opinions on the issue.

The 'Canadian' Criteria have been with us since 2003, they have been subject to some validation as an effective means of establishing severely impaired 'ME/CFS' sufferers by Leonard Jason et al (2005) and, crucially, have been subject to the most studious of neglect and ignoring, in most subsequent research papers on 'CFS'.

Recently, Lombardi et al's use of the Canadian criteria to select a research patient cohort, and the failure of, specifically, Erlwein et al to reproduce this cohort (but also, I argue , the Kerr team's apparent failure to do same) has highlighted both the failure of scientists to establish a severely impaired research cohort, and the inappropriate extrapolation of results from research cohorts, for which organic dysfunction has been weeded out, to severely impaired patients with signs and symptoms of organic illness (no matter how difficult to 'explain' fully). I think therefore the issue has become extremely timely.

There is a dissonance between what many in the community understand about patient cohorts, and the apparent lack of this by some of the 'scientists'. This is not meant to be inflammatory, but I do think we need to stop excusing scientists for not establishing more 'Canadian' cohorts in ME/CFS research, or at least acknowledging, in the sections of their papers detailing 'limitations of study', the discrepancies between those cohorts like the 'empirical' CDC and Wessley/White Oxford/minimal Fukuda criteria cohorts, and people who should be included in a Canadian defined research cohort, perhaps (I'd say definitely) with the additional abnormal physiological responses detailed in the Lombardi paper.

I have been involved since about 2004 in highlighting the failure of the 'PACE' trial in particular to establish a cohort of patients based on the Canadian guidelines, as well as other scientist's failures to acknowledge the problems of conflicting patient cohorts in their published papers (for example under a section detailing 'limitations of the study') since 2003. I will put up various links and copies of correspondence etc detailing this.

Failure to establish a research cohort of 'Canadian' patients in the UK means there will never be an adequate replication study in the UK. In addition, it has allowed certain unsubtantiated but common claims to be made (e.g. the recent BMJ editorial by Sandthouse et al) that people as ill as, for example, Lynne Gilderdale, are somehow 'rare' and that 'CFS' is treatable by CBT/GET.

I would like this thread to include links to any deliberations on the Canadian Criteria as a research tool, including those arguing against it. In light of some doubt being cast upon the research cohort in the Lombardi et al paper, I am hoping to get that issue clarified as well.

Any evidence people have around the use or non use of Canadian criteria in research settings would be greatly appreciated, as well as deliberations and opinions on the issue.

Best wishes
Angela Kennedy

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Hi Angela Welcome

I know they all had immuno probems but I would like to know exactly what symptoms they had in common.The Uk government know that post exhertional malaise/fatigue is the defining symptom yet they commission studies with patients lacking this core symptom.They then compound the felony with underpowered studies producing confidence intervals wide enough to drive a double decker bus through and thus make extrapolation into a population impossible even if they had used matched groups which they dont.They then confuse correlation with causation and produce r values out of disneyland!This travesty then gets published despite being refereed by a known associate of the author(s)-How!

The IACFS/ME will be working on turning the " Canadian" criteria into a research tool to select cohorts among other things. Check out CBS/Shane's thread and the letters between him and IACFS/ME president Fred Friedberg:

I know they all had immuno probems but I would like to know exactly what symptoms they had in common.The Uk government know that post exhertional malaise/fatigue is the defining symptom yet they commission studies with patients lacking this core symptom.They then compound the felony with underpowered studies producing confidence intervals wide enough to drive a double decker bus through and thus make extrapolation into a population impossible even if they had used matched groups which they dont.They then confuse correlation with causation and produce r values out of disneyland!This travesty then gets published despite being refereed by a known associate of the author(s)-How!

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Thanks for the kind welcome Gerwyn.

So you've noticed a few problems in the research literature then? ; )

Your analysis is spot on, of course - the range of methodological flaws alone in literature claiming psychiatric aetiology to 'CFS' is striking, especially the more you become immersed in it : (

The IACFS/ME will be working on turning the " Canadian" criteria into a research tool to select cohorts among other things. Check out CBS/Shane's thread and the letters between him and IACFS/ME president Fred Friedberg:

Oh no,what kind of patients are actually being studied is an issue worldwide!

Remember the Canadian criteria are really clinical guidelines meant to assist physicians. Even then, few physicians are aware of them or use them.

Peterson has been using them for years and the WPI study has put them in the forefront as a research tool.

It would be fabulous if the IACFS/ME could use them to create an international research definition.

Remember, the "I" in IACFS/ME stands for "international", so if this project suceeds, it should help you in the UK as well.

I'm encouraged that the IACFS/ME has been more pro-active of late. Friedberg's testimony at the past two US CFSAC meetings was great.

With more funding from outside sources and the backing of patients, let's hope we see some action on the development of research criteria. I was heartened when Dr. Klimas a year or two ago ( when she was president of the organization), let it be known that coming up with clinical guidelines was on the front burner. Unforunately, it did not turn out that way, as we now know.

It won't be easy for the IACFS/ME to do this as it's a broad, diverse group and those running it are already quite active in their fields and volunteer their time to the organization.

There are many organizations worthy of funding and I don't usually plug one, but becoming a member of the IACFS/ ME might be quite worthwhile.

This cohort-selection is a huge problem worldwide. In the U.S. the CDC use the Fukuda definition which ends up classifying people with just depression as having CFS. We have to do what we can to fight this!

I think it's important to note that Dr.Peterson was a co-author (if not the main author) of the Canadian criteria. It is likely that this fact would play in to the political silliness of this all. At the very least, for those who are in an opposing camp, they would be reticent to accept it regardless of how useful it may be.

Like most here speaking up, I feel it is extremely important to use the Canadian Consensus Critieria. These came from a diverse panel of very experienced clinicians working with ME/CFS patients, which the other criteria did not. To generalize, I would say the Canadian critieria emphasize the critical neurological aspects, which drive the whole systemic disorder, the other parts, including the Post Exertional Malaise. That is how I see it.

It's all dubious reasoning e.g. the study by Wessely he refers to to claim more symptoms (from the CDC critieria definition) means more psychopathology was clearly done on CFS patients. Also many psych criteria use symptoms such as sleep problems, memory problems, fatigue, etc to diagnose them so it's not surprising there is a correlation.

I forget exactly but imagine he has been giving the same opinions in other places.
He has/had "the ear" of Bill Reeves who said he (PDW) was very intelligent.

Don't have the exact time unfortunately when he brings the issue up - one can probably get an idea from where it is in the slides.

I think people should be very wary of any committees Peter White is on. He doesn't like to compromise and can seem to some that he is making fair points (i.e. people can be taken in by him).

It's all dubious reasoning e.g. the study by Wessely he refers to to claim more symptoms (from the CDC critieria definition) means more psychopathology was clearly done on CFS patients. Also many psych criteria use symptoms such as sleep problems, memory problems, fatigue, etc to diagnose them so it's not surprising there is a correlation.

I forget exactly but imagine he has been giving the same opinions in other places.
He has/had "the ear" of Bill Reeves who said he (PDW) was very intelligent.

Don't have the exact time unfortunately when he brings the issue up - one can probably get an idea from where it is in the slides.

I think people should be very wary of any committees Peter White is on. He doesn't like to compromise and can seem to some that he is making fair points (i.e. people can be taken in by him).

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How can you have a neurological disorder without neurological cns autonomic symptoms The canadian criterea are the only logical criterea to use!

I think it's important to note that Dr.Peterson was a co-author (if not the main author) of the Canadian criteria. It is likely that this fact would play in to the political silliness of this all. At the very least, for those who are in an opposing camp, they would be reticent to accept it regardless of how useful it may be.

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Peterson is one of the co-authors, along with Klimas, De Meirleir, Lerner and others, but I believe the main (and corresponding author) is Bruce M. Carruthers. This document has been known in the literature for quite some time, and represents the efforts of researchers who are better known for their medical expertise than many in the opposing camp (i.e. Wessely and friends in the UK, probably a couple old guard CDC and NIH people in the States). Also, it would be easy to point out that Wessely et al were involved in the formation of the Oxford Criteria which they use, and which is even less selective, and thus clinically less useful, than the Fukuda criteria. Therefore I think that any attempt to put political spin to Peterson's association would be ineffective, and probably backfire. I would think 'they' already know this.

I think this is an ideal - not to mention necessary - 'wedge issue' with which to push for the broader implementation of the Canadian criteria. If XMRV-ME/CFS studies must use them, and the rationale is understood, the research community will already by necessity begin to shift toward its broader adoption. The CDC is currently collaborating with Dr. Mikovits in attempting to replicate the WPI studies.. what better time will there be to lobby for the CDC's adoption of the Canadian criteria (and of course abandonment of the Reeves' 'Empirical' definiton, esp. since his departure) than when they themselves are most likely being obliged to use it?

Angela:

We have indeed had our own problems with cohorts in "CFS" studies over here, most notably since the CDC began to use the new "Empirical Definition" which is similar to the Oxford in its breadth.

You may already have all the following documents, but hey, you asked for links... is this sort of what you had in mind?

Leonard Jason has authored a few good studies that found serious flaws in the Fukuda 1994 definition (not to mention the Empirical) and contrasted it with the Canadian Consensus criteria, which he found much more effective. Some of these can be found on the NAME-US site here; you just have to scroll down to the section on "Case Definition Studies" for the pdf's:http://www.name-us.org/ResearchPages/ResJason.htm#Case_Definition_Studies

"The current U.S. case definition for CFS (Fukuda et al., 1994) is characterized by vaguely worded criteria that lack operations definition and guidelines to assist health care professional in their interpretation and application of the diagnostic too. (Jason et al., 1999d). The Canadian case definition [includes] these critical symptoms and use of such types of case definitions might aid in the selection of more homogeneous samples.

I think this is an ideal - not to mention necessary - 'wedge issue' with which to push for the broader implementation of the Canadian criteria. If XMRV-ME/CFS studies must use them, and the rationale is understood, the research community will already by necessity begin to shift toward its broader adoption. The CDC is currently collaborating with Dr. Mikovits in attempting to replicate the WPI studies.. what better time will there be to lobby for the CDC's adoption of the Canadian criteria (and of course abandonment of the Reeves' 'Empirical' definiton, esp. since his departure) than when they themselves are most likely being obliged to use it?

(Above is a quote from Dr. Yes.) And I add, Yes, I think we ought to push for the Canadian Criteria as the standard definition. It is essential for the replication study and for consistency with other, future studies too.

@ Dr Yes: Yes! Those links are what I've got in mind. I think it might be useful to have deliberations on CG in one place, so that people can refer to them, especially as, I suspect, many of us will have occasion to use such resources in the near future, as more 'negative' XMRV studies might come out, certainly as PACE comes out. But while Canada gets ignored, ALL subsequent CFS research not using it is in danger of being fundamentally flawed, and of course, much past research is problematic for that reason too -which is an unpleasant and sobering thing to have to consider.

@ Tom Thank you for the Peter White link - I had forgotten about that one!

@ Sing, Julius, Gerwyn teejikay totally agree with your comments.

At the very least, any paper subsequent to 2003 should have mentioned it's own project cohort discrepancy with Canadian Criteria (in a 'limitations of study' section at least). All subsequent papers should, and where possible, community members might have to bring this up when providing critiquing responses, perhaps? It is amazing this problem has been neglected for so long by scientists.

Furthermore, the WPI give this information about their patient cohort in their supporting online material:

"Their diagnosis of CFS is based upon prolonged disabling fatigue and the presence of cognitive deficits and reproducible immunological abnormalities. These included but were not limited to peturbations of the 2-5A synthetase/RNase L antiviral pathway, low natural killer cell cytotoxicity (as measured by standard diagnostic assyas) and elevated cytokines particularly interleukin-6 and interleukin-8. In addition to these immunological abnormalities, the patients characteristically demonstrated impaired exercise performance with extremely low VO2 max measured on stress testing..." (www.sciencemag.org/cgi/content/full/117905/DC1)

In any British subsequent research to Lombardi et al, unless the patient cohort selected was similar enough to that in the Lombardi research, it is premature to believe XMRV is not present in the 'CFS' population in Britain.

Ongoing neglect of the importance of establishing a possible ‘CFS’ patient population in Britain, clinically and in research settings, using the Canadian Guidelines, is preventing the development of knowledge that might help extremely ill and disabled people, diagnosed with 'CFS', known to be here in Britain.

**I am therefore interested if the authors are aware of any serious attempts to identify such a population in Britain, or taking part in such attempts themselves. **

The problems I have briefly outlined here do not fully express the range and depths of problems with regard to: the identity of an accurate ‘CFS’ population; the instabilities of ‘CFS’ criteria per se; the faulty concepts of ‘medically unexplained’ or ‘functional‘ and relation to ‘psychogenic‘ explanations for somatic illness; the vagaries of criteria that claim to facilitate a ‘diagnosis of exclusion’; and the psychogenic dismissal of serious organic dysfunction of patients given a ’CFS’ diagnosis, problems that have happened for many years.

I don't know exactly what the official guidance for doctors in Scotland will be when it finally gets published but when they were debating it they agreed the Canadian guidelines were the best for diagnosing ME.

The opposition demanded to know what would be done for patients who didn't fulfill the criteria and said they deserved medical treatment as well and what wold happen to them if the guidelines were adopted.

No one seems to worry that those of us who fulfill the guidelines are ignored jst now.